Independent effects of diet and exercise training on fat oxidation in non-alcoholic fatty liver disease

AIM To investigate the independent effects of 6-mo of dietary energy restriction or exercise training on wholebody and hepatic fat oxidation of patients with nonalcoholic fatty liver disease(NAFLD).METHODS Participants were randomised into either circuit exercise training(EX;n = 13;3 h/wk without changes in dietary habits),or dietary energy restriction(ER) without changes in structured physical activity(ER;n = 8).Respiratory quotient(RQ) and whole-body fat oxidation rates(Fatox) were determined by indirect calorimetry under basal,insulin-stimulated and exercise conditions.Severity of disease and steatosis was determined by liver histology;hepatic Fatox was estimated from plasma β-hydroxybutyrate co.ncentrations;cardiorespiratory fitness was expressed as VO2 peak.Complete-case analysis was performed(EX:n = 10;ER:n = 6).RESULTS Hepatic steatosis and NAFLD activity score decreased with ER but not with EX.β-hydroxybutyrate concentrations increased significantly in response to ER(0.08 ± 0.02 mmol/L vs 0.12 ± 0.04 mmol/L,P = 0.03) but remained unchanged in response to EX(0.10 ± 0.03 mmol/L vs 0.11 ± 0.07 mmol/L,P = 0.39).Basal RQ decreased(P = 0.05) in response.to EX,while this change was not significant after ER(P = 0.38).VO_(2peak)(P < 0.001) and maximal Fa_(tox) during aerobic exercise(P = 0.03) improved with EX but not with ER(P > 0.05).The increase in β-hydroxybutyrate concentrations was correlated with the reduction in hepatic steatosis(r =-0.56,P = 0.04).CONCLUSION ER and EX lead to specific benefits on fat metabolism of patients with NAFLD.Increased hepatic Fat_(ox) in response to ER could be one mechanism through which the ER group achieved reduction in steatosis.

Genetics and pathophysiology of mammalian sulfate biology

Nutrient sulfate is essential for numerous physiological functions in mammalian growth and development. Accordingly, disruptions to any of the molecular processes that maintain the required biological ratio of sulfonated and unconjugated substrates are likely to have detrimental consequences for mammalian physiology. Molecular processes of sulfate biology can be broadly grouped into four categories： firstly, intracellular sulfate levels are maintained by intermediary metabolism and sulfate transporters that mediate the transfer of sulfate across the plasma membrane; secondly, sulfate is converted to 3＇-phosphoadenosine 5＇-phosphosulfate （PAPS）, which is the universal sulfonate donor for all sulfonation reactions; thirdly, sulfotransferases mediate the intracellular sulfonation of endogenous and exogenous substrates; fourthly, sulfate is removed from substrates via sulfatases. From the literature, we curated 91 human genes that encode all known sulfate transporters, enzymes in pathways of sulfate generation, PAPS synthetases and transporters, sulfotransferases and sulfatases, with a focus on genes that are linked to human and animal pathophysiology. The predominant clinical features linked to these genes include neurological dysfunction, skeletal dysplasias, reduced fecundity and reproduction, and cardiovascular pathologies. Collectively, this review provides reference information for genetic investigations of perturbed mammalian sulfate biology.

Assembly of a parts list ofthe human mitotic cell cycle machinery

The set of proteins required for mitotic division remains poorly characterized. Here, an extensive series of correlation analyses of human and mouse transcriptomics data were performed to identify genes strongly and reproducibly associated with cells undergoing S/G2-M phases of the cell cycle. In so doing, 701 cell cycle-associated genes were defined and while it was shown that many are only expressed during these phases, the expression of others is also driven by alternative promoters. Of this list, 496 genes have known cell cycle functions, whereas 205 were assigned as putative cell cycle genes, 53 of which are functionally uncharacterized. Among these, 27 were screened for subcellular localization revealing many to be nuclear localized and at least three to be novel centrosomal proteins. Furthermore, 10 others inhibited cell proliferation upon siRNA knockdown. This study presents the first comprehensive list of human cell cycle proteins, identifying many new candidate proteins.